Impact of Mechanical Vibrations on the Performance of Integrated Navigation Systems and On Optimal IMU Specification

Jan Wendel and Gert F. Trommer

Abstract:	This paper presents investigations on the relationship of inertial sensor accuracy and system performance of GPS aided missile navigation systems in the presence of high mechanical vibration levels. The inertial sensor data provided by an IMU under missile air carriage conditions were analysed to obtain a model of the measurement noise process. Compared to the standard IMU specification case which usually assumes low intensity white noise, we found a second order VAR process with drastically increased covariance matrix as well as strong correlations in time and between the data of the six inertial sensors. Therefore, an Extended Kalman Filter (EKF) with 15 state-variables, assuming white inertial sensor noise and an EKF with 27 state-variables, modelling the real measurement noise process by means of an appropriate shaping filter, were investigated. Monte Carlo simulation runs were used to compare the performance of both filters for different navigation sensor accuracies with focus on the ability of IMU bias estimation in the case of GPS aiding and the system performance in the case of GPS loss situations. The simulation results indicate in the case of strong missile vibrations that a significant improvement by the estimation of inertial sensor biases is not possible any longer, allowing the omission of the respective state- variables. As the primary error source turns out to be the noise process, significant relaxations of IMU performance specifications does not imply a major degradation of navigation performance.
Published in:	Proceedings of the 57th Annual Meeting of The Institute of Navigation (2001) June 11 - 13, 2001 Albuquerque, NM
Pages:	614 - 621
Cite this article:	Wendel, Jan, Trommer, Gert F., "Impact of Mechanical Vibrations on the Performance of Integrated Navigation Systems and On Optimal IMU Specification," Proceedings of the 57th Annual Meeting of The Institute of Navigation (2001), Albuquerque, NM, June 2001, pp. 614-621.
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